Question about the key to flying

Pour yourself a drink and enjoy this long thread ALL about keys with a lot of information that you didn’t know you didn’t know!:D

http://www.pprune.org/forums/showthread.php?t=278770&highlight=Plane+keys

Thanks very much for that Deano! Very clear response to my muddled questions :p Another gap in aircraft knowledge: filled in!

Oops, missed the next section of your question

As for aircraft parked in the desert, yes theoretically you can start them from battery power provided they have sufficient charge in them, if not then you may be able to fire up the APU, again if not then a GPU would be needed.

As for the doors most doors I know of are mechanically sealed so you can open the doors without power, the forward port pax door and aft baggage door on my a/c is air sealed once closed by using air from the de-ice system.

Symon

Basically it will be connected to a GPu if, and only if one is available at the airfield it is at, normally this would be DC power, our aircraft has the capability to be connected to AC power but you cannot start the engines with AC power as the TRUs aren’t powerful enough to turn the starter generators.
As for the APU no you don’t need a GPU connected to start the APU, basically if you enter a cold & dark cockpit the first thing you need is power, so as I said before you can achieve this in 1 of 3 ways, battery power, APU or a GPU, if you decide to use battery power then of course they are going to discharge, so this is a bad thing, this is why you would either start the APU straight away, and to do this you give it power (from the battery) then do the relevant fire test, then start it, once it comes online you can then run the APU generator which gives the aircraft power and charges the batteries. If you decide not to use the APU then you can use the GPU, the GPU supplies the aircraft with power in the same concept as the APU.
So in effect no you don’t need the GPU for the APU to run, they are both there to do the same job so you would use one or the other.
As soon as you have the engines running you can then use the engine DC generators to supply power and charge the batteries thus being in a position to disconnect the GPU or APU.
If Ground Power was unavailable and the APU won’t start (as it sometimes doesn’t) then you are left with the batteries to start the engines, so it’s best not to spend eons with everything switched on whilst you do your checks etc before you start the engines. If the battery voltage drops below a certain amount then you can’t use them for starting so it’s best you ask for start clearance sooner rather than later.

Clear as mud? thought so 🙂

Yeah, that all helps fill some curiosity, thanks 🙂 So if an aircraft is sitting on an airfield or in a hanger it will be connected to a GPU so that you can start the APU? Or do you just spool the engines up for power using a GPU? What about stored aircraft in the desert? Can they be started back up on battery power or would they need a portable generator connected?

Also, sorry, can the doors be shut/open purely mechanically? Or would you need a GPU connected to open a door of a sealed aircraft that hasn’t been used recently?

These are all just questions of pure random intrest, thanks for any answers 😀

Symon

Judas

Basically no there are no keys for turbine powered aircraft. Firstly you need power to the aircraft, this comes from one of 3 sources, the batteries, the APU or a GPU (Ground Power Unit).
Without spending eons typing in detail about type specifics generically you have starter generators that are triggered by switches in the cockpit to start the starting sequence, which generally start turning the HP or LP compressor, once you have rotation you can insert the fuel and ignite it, the starter switch should go out turning the starter generator into a generator to provide power, you can then disconnect the GPU or switch off the APU.
There are certain limitations to starting with battery power, the batteries have to have a certain load before it can be used, and as CKing says it’s best to keep the batteries off when on ground power and you leave the aircraft because if the GPU runs out of fuel or drops offline you will drain the batteries, on the type I am on you cannot do any type of start if the standby battery is flat.

Hope this helps

The start procedure on an Airbus seems greatly simplified with technology.

I think only light aircraft really have keys?

Doors are opened manually with the handles from the outside.

The main thing on an airbus is turning the Battery Packs off as this turns off all the systems in the cockpit. Unsure of Cabin Systems.

The cabin will still have power for the cleaners. I always turn turn the batteries off if I leave an aircraft for any length of time. If the ground power drops off line the batteries will not be discharged trying to keep various essential services powered.

To “wake” an airliner up requires a number of systems to be switched on after the relevent safety precautions have been observed. There isn’t one “Master switch” that does them all.

Rgds Cking

Doors are opened manually with the handles from the outside.

The main thing on an airbus is turning the Battery Packs off as this turns off all the systems in the cockpit. Unsure of Cabin Systems.

Are you planning on nicking one dude cos it sounds like it :dev2: